CN116364200A - Method for determining flotation design time based on laboratory flotation closed-circuit test - Google Patents

Abstract

The invention discloses a method for determining the design time of flotation based on laboratory flotation closed-circuit test, which is determined according to the data obtained in the flotation closed-circuit test, the data includes the minimum number of test groups required to reach the equilibrium state in the test, and the The total weight of middlings in a single group of tests after the equilibrium state and the data of the supplementary water amount of the single group of tests after reaching the equilibrium state. The present invention can accurately calculate the flotation design time, thereby realizing a high degree of fitting between the flotation design time and the closed-circuit flotation test time in the laboratory, making a reasonable evaluation of the flotation time of the existing production process, and can also be used for subsequent technological processes Design and equipment selection provide accurate data, suitable for most metal ore beneficiation process design and process diagnosis, with the characteristics of simple calculation and strong practicability.

Description

Method of Determining Flotation Design Time Based on Laboratory Flotation Closed Circuit Test

technical field

The invention relates to a method for determining the design time of flotation.

Background technique

Flotation is widely used in the separation of metallic minerals, non-metallic minerals, and chemical raw material minerals.

In the production of the dressing plant, the sum of the flotation time of the roughing operation and each sweeping operation is called the flotation time. Flotation time is an important control parameter in the flotation control process, which is closely related to the flotation effect. Every kind of ore has its suitable flotation time. If the flotation time is too short, the recovery rate will be low; if the flotation time is long, the recovery rate will increase, but the quality of the concentrate will decrease, and at the same time, more flotation machines will be required, which will increase the construction investment and operation energy consumption of the concentrator, resulting in an increase in the beneficiation cost .

In the existing flotation control process, there are several different ways to determine the flotation time:

1. When designing the flotation of the dressing plant, first determine the total time t ₀ of the roughing and sweeping of the flotation _test process through the open circuit test in the laboratory. For the actual flotation time in industrial production, multiply _t0 by an amplification factor k to determine the final flotation design time of the concentrator, so as to control the flotation process. After reviewing the literature, the amplification factor k value is an empirical data, and there are few articles and reports on the selection basis of the k value. The k value of foreign dressing plants is generally 2, and the domestic k value is generally 1.5.

Two, the empirical calculation formula of flotation time also proposed in the prior art is as follows:

In the formula, T—design time of flotation, min;

t ₀ —the flotation time determined by the test, min;

q ₀ —air filling capacity of test flotation machine, m ³ /(m ² ·min);

q—inflation capacity of industrial flotation machine, m ³ /(m ² ·min);

Δt—the flotation time increased according to the production practice, min.

However, for the above empirical formulas, different literatures have different values. : Refer to "Mineral Processing Design Manual", the first edition in July 1988 published by Beijing Metallurgical Industry Press, Δt=0.5×k×t ₀ , the unit is min, and k=1.5~2 is generally taken. With reference to "Flotation", the first edition in August 2018 published by Beijing Metallurgical Industry Press, Δt=k×t ₀ , the unit is min, and k=1.5~2 is generally taken.

It can be seen that even when the test conditions and data are consistent, the flotation design time obtained by different calculation methods will be quite different. For example, the flotation design time based on the document "Mineral Processing Design Manual" is shorter than that based on the document "Flotation". The former may easily lead to low recovery rate, while the latter may lead to problems such as low concentrate quality, increased production and investment costs, etc. .

Contents of the invention

The present invention proposes a method for determining flotation design time based on laboratory flotation closed-circuit test, the purpose of which is to provide accurate flotation design time and avoid low recovery rate and concentrate concentration caused by unreasonable flotation time. Problems such as poor quality and high investment can also be used as reference data for equipment selection, process reconstruction and expansion.

Technical scheme of the present invention is as follows:

A method for determining the flotation design time based on the laboratory flotation closed-circuit test. The flotation design time is determined according to the data obtained in the flotation closed-circuit test. The total weight of middlings in a single group of tests after the equilibrium state and the data of the supplementary water amount of the single group of tests after reaching the equilibrium state.

As a further improvement of the method for determining the flotation design time based on the laboratory flotation closed-circuit test, the calculation formula of the flotation design time is:

Among them, n represents the number of test groups when the laboratory closed-circuit flotation test _reaches equilibrium for the first time; _t0 represents the time of the flotation open-circuit test, and the unit is min; Weight, the unit is g; m ₀ represents the dry weight of the raw ore sample given to the single group test in the flotation closed circuit test, the unit is g; V _w represents the additional water volume of the single group test in the closed circuit test, the unit is ml; V ₀ Represents the volume of the flotation cell used in the closed-circuit test, in ml; q ₀ represents the gas filling capacity of the test flotation machine, in the unit of m ³ /(m ² min); q represents the gas filling capacity of the industrial flotation machine, in the unit of m ³ / (m ² ·min).

As a further improvement of the method for determining the flotation design time based on the laboratory flotation closed-circuit test: the laboratory flotation closed-circuit test adopts the method of cyclic flotation, and each round of flotation produces concentrate, tailings and middle ore , the medium ore will be flotation again together with the raw ore newly added in the next round.

As a further improvement of the method for determining the flotation design time based on the laboratory flotation closed-circuit test: after the flotation closed-circuit test is completed, calculate the yield of the concentrate and tailings and the grade of the tailings, if there is a The integer n' can satisfy the following conditions at the same time:

(a) Since the n'th test, the fluctuation range of the total yield of concentrate and tailings is less than the preset value;

(b) Since the n'th test, the fluctuation range of the tailings grade is less than the preset value;

Then take the integer n' as the number n of test groups when the balance state is reached for the first time.

As a further improvement of the method for determining the flotation design time based on the laboratory flotation closed-circuit test: each round of laboratory flotation closed-circuit test includes a roughing, a selection and two sweeps, the steps are as follows:

(1) Start the first round of test, add raw ore, carry out roughing, obtain roughing concentrate and roughing tailings; Carry out the first screening to obtain the scavenging concentrate and scavenging tailings; use the selected tailings and scavenging concentrate as the first middle ore; carry out the second scavenging on the scavenging tailings to obtain the tailings and The second middle mine: record the amount of additional water, weigh the concentrate and tailings after pressure filtration, and wait for the closed-circuit test to be uniformly dried and weighed to test the grade;

(2) start the next round of test, will add the new raw ore and the first middle ore of the last round and carry out roughing together to obtain roughing concentrate and roughing tailings; ore and concentrated tailings; the first round of roughing tailings and the second middle ore of the previous round are carried out together to obtain scavenging concentrate and scavenging tailings; the selected tailings and scavenging concentrate As the first middle ore of this round; carry out the second sweep of the tailings to obtain the tailings and the second middle ore of this round; record the amount of additional water, filter the concentrate and tailings and weigh them for later use , after the closed-circuit test is completed, it will be uniformly dried and weighed to test the grade;

(3) return the first medium ore and the second medium ore of this round to the flotation process, repeat step (2), and carry out the next round of test; After the final weight data is stable, continue to do 1 to 2 rounds of tests, and then dry and weigh the middle ore filter press of the last group of tests, and record the weight.

Compared with the prior art, the present invention has the following beneficial effects:

The invention obtains the required test data by carrying out laboratory flotation closed-circuit test on ore samples, and accurately calculates the flotation design time according to the new correction formula, thereby realizing the high degree of approximation between the flotation design time and the laboratory closed-circuit flotation test time. Combined, it eliminates the extensive error of the empirical algorithm of flotation design time, makes a reasonable evaluation of the flotation time of the existing production process, and can also provide accurate data for subsequent process design and equipment selection, avoiding the flotation time caused by excessive flotation time. Short or too long lead to problems such as recovery rate, low concentrate quality, increased production and investment costs. This method is applicable to the design and process diagnosis of most metal ore beneficiation processes, and has the characteristics of simple calculation and strong practicability.

Further, the equilibrium state is judged by the total yield of fine tailings and the fluctuation of tailings grade. When both of them reach a stable state, it indicates that the middle ore in the first group of flotation closed-circuit tests has been completely separated. Selection, flotation closed-circuit test The time from the start of the second group of tests to the first equilibrium state is the time required for the first group of middle ore separation. Preliminary determination of the flotation design time based on this time can ensure that the flotation time is sufficient, so that the middle ore can be effectively sorted, and at the same time, it can avoid the situation that the concentrate grade decreases and the tailings grade increases.

On the other hand, the present invention fully takes into account the difference between the flotation closed-circuit test and the field production: one, the stability of the liquid level of the flotation machine in the field production mainly depends on continuous feeding, so the concentration of the ore pulp is relatively stable, while the test requires Continuously add clear water to keep the liquid level high, resulting in a slow decline in the pulp concentration; second, the aeration effect of the test flotation machine is better than that of the production flotation machine, and the flotation rate is higher. In view of the above problems, the present invention further corrects the calculation results according to the data of the amount of water replenishment and the amount of air inflated in the test, which eliminates the impact of the above differences, improves the accuracy of the flotation parameters, improves the flotation effect, reduces cost.

Description of drawings

Figure 1 is a schematic flow chart of the closed-circuit test.

Detailed ways

The technical scheme of the present invention is described in detail below in conjunction with accompanying drawing:

A method for determining the flotation design time based on a laboratory flotation closed-circuit test, the core of which is to determine the flotation design time according to the data obtained in the flotation closed-circuit test. The laboratory flotation closed-circuit test adopts the method of cyclic flotation, and each round of flotation produces concentrate, tailings and middlings, and the middlings are flotation again together with the raw ore newly added in the next round. The data include the minimum number of test groups required to reach the equilibrium state in the test, the total weight of middlings in a single group test after reaching the equilibrium state, and the additional water volume data of the single group test after reaching the equilibrium state.

As shown in Figure 1, each round of laboratory flotation closed-circuit test includes a rough selection, a selection and two sweeps, and the specific steps are as follows:

(1) Start the first round of test, add raw ore, carry out roughing, obtain roughing concentrate and roughing tailings; Carry out the first screening to obtain the scavenging concentrate and scavenging tailings; use the selected tailings and scavenging concentrate as the first middle ore; carry out the second scavenging on the scavenging tailings to obtain the tailings and The second medium mine: record the amount of additional water, weigh the concentrate and tailings after pressure filtration, and wait for the closed-circuit test to be uniformly dried and weighed to test the grade.

In this embodiment, medium ore products are taken in a 3L beaker. After the test is completed, all concentrate and tailings products should be dried, weighed and assayed. In order to preliminarily judge whether the test product has reached equilibrium, it is preferable to filter each group of concentrate during the test, and weigh the wet weight of the filter cake.

(2) start the next round of test, will add the new raw ore and the first middle ore of the last round and carry out roughing together to obtain roughing concentrate and roughing tailings; ore and concentrated tailings; the first round of roughing tailings and the second middle ore of the previous round are carried out together to obtain scavenging concentrate and scavenging tailings; the selected tailings and scavenging concentrate As the first middle ore of this round; carry out the second sweep of the tailings to obtain the tailings and the second middle ore of this round; record the amount of additional water, and weigh the concentrate and tailings after filtration. After the closed-circuit test is finished, it is uniformly dried and weighed to test the grade.

(3) Return the first medium ore and the second medium ore of this round to the flotation process, repeat step (2), and carry out the next round of test. After the concentrate and tailings of each round of flotation are filtered After the weight data is basically stable, continue to do 1-2 rounds of tests. Dry and weigh the middle ore filter press of the last group of tests, and record the weight.

Under normal circumstances, 5-8 groups of closed-circuit experiments should be done one after another. Whether the test is balanced is marked by whether the metal content and yield of the flotation products of the last few sets of tests are approximately equal. The specific criteria for judging are: after the closed-circuit test, all samples shall be weighed and assayed, and the yield of concentrate and tailings and the grade of tailings shall be calculated. If there is an integer n' as small as possible, the following conditions may be satisfied at the same time:

(a) Since the n'th test, the fluctuation range of the total yield of concentrate and tailings is less than the preset value;

(b) Since the n'th test, the fluctuation range of the tailings grade is less than the preset value;

Then take the integer n' as the number n of test groups when the balance state is reached for the first time.

Since both the raw ore and the middle ore enter the same set of process equipment for separation, the flotation time of the middle ore and the raw ore must be consistent. Compared with the original ore, the target minerals in the middle ore are finer in size, lower in dissociation, and more tightly combined with gangues, making it difficult to sort. Therefore, the flotation time required for complete separation of medium ore is longer than that of raw ore. If the flotation time is insufficient, the middling ore is not effectively sorted, and the amount of middling ore will continue to increase and fail to reach a balance, or the grade of the concentrate will continue to decline, and the grade of the tailings will continue to rise. In order to ensure sufficient flotation time for medium ore and ensure the stability of process indicators, the flotation time of raw ore must be extended to the flotation time of medium ore. Therefore, the present invention finds that the total yield of fine tailings and the grade of tailings have reached a stable equilibrium state through the above judgment criteria. At this time, the middle ore in the first group of tests of the flotation closed circuit test has been completely sorted, and the flotation The time from the start of the second group of closed-circuit tests to the first equilibrium state is the time required for the first group of middle ore separation. Preliminary determination of the flotation design time based on this time can ensure sufficient flotation time so that middlings can be effectively separated.

In this example, the mass of the raw ore sample fed into each group of tests is 1000g, the grade is 1.91g/t, and the density is 2.75t/m ³ , and a flotation machine with a flotation cell volume of 3L is used for roughing and sweeping. The flotation test time is: 4 minutes for roughing, 4 minutes for beneficiation, 3 minutes for the first scavenging and second scavenging, and the grade of flotation tailings is required to be lower than 0.12g/t. The relevant data are obtained in Table 1.

Table 1 Statistical table of ore sample flotation closed-circuit experiment data

From the analysis of the data in the table, it can be seen that in Group 5 of the flotation closed-circuit test, the yield of concentrate and tailings reached a balanced state, and the grade of tailings was stable at 0.1g/t.

The calculation formula of flotation design time is:

Among them, n represents the number of test groups when the laboratory closed-circuit flotation test _reaches equilibrium for the first time; _t0 represents the time of the flotation open-circuit test, and the unit is min; Weight, the unit is g; m ₀ represents the dry weight of the raw ore sample given to the single group test in the flotation closed circuit test, the unit is g; V _w represents the additional water volume of the single group test in the closed circuit test, the unit is ml; V ₀ Represents the volume of the flotation cell used in the closed-circuit test, in ml; q ₀ represents the gas filling capacity of the test flotation machine, in the unit of m ³ /(m ² min); q represents the gas charging capacity of the industrial flotation machine, in the unit of m3/( m2·min).

n=5, m _z =494.9g, m ₀ =1000g, t ₀ =10min, q ₀ =2.78m ³ /(m ² ·min), q=2m ³ /(m ² ·min), V _w = 1550ml is substituted into the above formula, and the flotation design time is calculated as:

Therefore, the flotation design time of the new mill-float production system is 34.1 minutes. In actual production, the flotation time of the process is calculated to be 34.6 minutes by sampling the process, which is slightly higher than the flotation design time. The reason is that maintaining the ideal process index requires fine control of the process, and the process has no reservation for expansion It is necessary to strictly control the amount of ore processed daily.

Claims (5)

1. A method for determining flotation design time based on laboratory flotation closed-circuit test, characterized in that: the flotation design time is determined according to the data obtained in the flotation closed-circuit test, and this data includes the required time for reaching equilibrium in the test. The minimum number of test groups, the total weight of middlings in a single group test after reaching the equilibrium state, and the data of the supplementary water volume of the single group test after reaching the equilibrium state. 2. the method for determining flotation design time based on laboratory flotation closed-circuit test as claimed in claim 1 is characterized in that, the calculation formula of flotation design time is:

Among them, n represents the number of test groups when the laboratory closed-circuit flotation test _reaches equilibrium for the first time; _t0 represents the time of the flotation open-circuit test, and the unit is min; Weight, the unit is g; m ₀ represents the dry weight of the raw ore sample given to the single group test in the flotation closed circuit test, the unit is g; V _w represents the additional water volume of the single group test in the closed circuit test, the unit is ml; V ₀ Represents the volume of the flotation cell used in the closed-circuit test, in ml; q ₀ represents the gas filling capacity of the test flotation machine, in the unit of m ³ /(m ² min); q represents the gas filling capacity of the industrial flotation machine, in the unit of m ³ / (m ² ·min). 3. the method for determining flotation design time based on laboratory flotation closed-circuit test as claimed in claim 2, is characterized in that: said laboratory flotation closed-circuit test adopts the mode of cyclic flotation, and each round of flotation produces fine The ore, tailings and middle ore, among which the middle ore will undergo flotation again with the next round of newly added raw ore. 4. the method for determining flotation design time based on laboratory flotation closed-circuit test as claimed in claim 3 is characterized in that: after the flotation closed-circuit test is completed, calculate the productive rate of concentrate and tailings and the grade of tailings, If there exists an integer n' as small as possible, the following conditions can be satisfied simultaneously: (a) Since the n'th test, the fluctuation range of the total yield of concentrate and tailings is less than the preset value; (b) Since the n'th test, the fluctuation range of the tailings grade is less than the preset value; Then take the integer n' as the number n of test groups when the balance state is reached for the first time. 5. the method for determining flotation design time based on laboratory flotation closed-circuit test as claimed in claim 3 or 4, is characterized in that: each round of laboratory flotation closed-circuit test comprises a rough selection, a fine selection and twice To scan, the steps are as follows: (1) Start the first round of test, add raw ore, carry out roughing, obtain roughing concentrate and roughing tailings; Carry out the first screening to obtain the scavenging concentrate and scavenging tailings; use the selected tailings and scavenging concentrate as the first middle ore; carry out the second scavenging on the scavenging tailings to obtain the tailings and The second middle mine: record the amount of additional water, weigh the concentrate and tailings after pressure filtration, and wait for the closed-circuit test to be uniformly dried and weighed to test the grade; (2) start the next round of test, will add the new raw ore and the first middle ore of the last round and carry out roughing together to obtain roughing concentrate and roughing tailings; ore and concentrated tailings; the first round of roughing tailings and the second middle ore of the previous round are carried out together to obtain scavenging concentrate and scavenging tailings; the selected tailings and scavenging concentrate As the first middle ore of this round; carry out the second sweep of the tailings to obtain the tailings and the second middle ore of this round; record the amount of additional water, filter the concentrate and tailings and weigh them for later use , after the closed-circuit test is completed, it will be uniformly dried and weighed to test the grade; (3) return the first medium ore and the second medium ore of this round to the flotation process, repeat step (2), and carry out the next round of test; After the final weight data is stable, continue to do 1 to 2 rounds of tests, and then dry and weigh the middle ore filter press of the last group of tests, and record the weight.

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